1. Field of the Invention
The present invention relates to a mobile apparatus for driving different objects into the ground by impact and, in particular, pegs for fixing posts or stakes.
It relates more particularly to an apparatus of the type comprising a carrier structure supporting a swinging element along which slides a mass whose movements are controlled by a cable connected to a driving device having a two stroke operating cycle, namely:
a first stroke during which the driving device raises the mass to the level of the upper part of the swinging element, and
a second stroke during which the driving device interrupts its traction force and free wheels so as to let the mass drop under the effect of its own weight.
Thus, at the end of its fall, the mass may strike directly or indirectly the object which it is desired to drive into the ground and which has been previously disposed at right angles to the lower end of the swinging element.
2. Description of the Prior Art
It proves that the construction of an apparatus of this kind entails the resoltuion of numerous problems.
A first problem results from the fact that while the element is being driven in, the impact point of the mass moves downwards. Consequently, it is advisable to provide an arrangement for permanently adapting the travel of the mass and, consequently, guiding thereof to the driving-in level of the object to be driven in. It should be noted in this connection that a solution which may be considered for resolving this problem may consist in using a tubular shaped element whose inner surface serves for guiding the mass and for initially introducing, into the inner part of this tubular element, the object to be driven in. Thus, during driving in, the part of the object projecting outwardly from the ground remains inside the tubular element and is permanently guided in the volume of the passage of the mass.
However, this solution has the disadvantage of limiting the shape of the objects to be driven in, to the dimensions of the inner volume of the swinging element. Furthermore, it is subject to frequent jamming, because of deformation of the objects to be driven in, inside the swinging element, under the effects of the impacts in particular in the case of a hard ground.
The aim of the invention is therefore first of all to overcome these drawbacks. For this, it proposes a longitudinally extendable swinging element whose length is permanently adapted to the height of the object during driving in thereof, and which provides perfect continuity of guidance of the mass whatever this length may be.